Many LED light manufacturers claim their lamps can be used for horticultural production. But do they provide the right wavelengths of light to meet plants’ needs?
Growers often ask Michigan State University horticulture professor Roberto Lopez if they can use the LED lamps available from their local home improvement store to induce flowering of their long day ornamental crops.
“Some growers in the Midwest ship flowering annual and perennial bedding plants into southern markets,” Lopez said. “Trying to grow these long day plants during February and March in the Midwest means they are being produced under short day conditions. Since incandescent bulbs have been phased out and compact fluorescent bulbs aren’t very effective, LEDs can be an affordable alternative.”
Growers want to know if the LEDs available from local retailers can be used as effective photoperiodic light sources. Studies by fellow Michigan State researcher Erik Runkle have shown that these LEDs work with some long day crops, but not all of them. This can pose a challenge for growers who produce a wide variety of crops.
“Another question I get from growers is related to the inexpensive horticultural LEDs offered on Amazon or other online retailers, some costing $10 or less,” Lopez said. “These lamps are considerably cheaper, sometimes $20 to $30 less than the LEDs being offered by other companies that manufacture horticultural LEDs. The growers want to know is there really much difference in the light delivered by the LEDs from different manufacturers. Growers also need to consider that not all lamps are designed to withstand greenhouse conditions.”